xref: /openbmc/qemu/target/xtensa/gdbstub.c (revision ba632924)
1 /*
2  * Xtensa gdb server stub
3  *
4  * Copyright (c) 2003-2005 Fabrice Bellard
5  * Copyright (c) 2013 SUSE LINUX Products GmbH
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19  */
20 #include "qemu/osdep.h"
21 #include "qemu-common.h"
22 #include "cpu.h"
23 #include "exec/gdbstub.h"
24 #include "qemu/log.h"
25 
26 enum {
27   xtRegisterTypeArRegfile = 1,  /* Register File ar0..arXX.  */
28   xtRegisterTypeSpecialReg,     /* CPU states, such as PS, Booleans, (rsr).  */
29   xtRegisterTypeUserReg,        /* User defined registers (rur).  */
30   xtRegisterTypeTieRegfile,     /* User define register files.  */
31   xtRegisterTypeTieState,       /* TIE States (mapped on user regs).  */
32   xtRegisterTypeMapped,         /* Mapped on Special Registers.  */
33   xtRegisterTypeUnmapped,       /* Special case of masked registers.  */
34   xtRegisterTypeWindow,         /* Live window registers (a0..a15).  */
35   xtRegisterTypeVirtual,        /* PC, FP.  */
36   xtRegisterTypeUnknown
37 };
38 
39 #define XTENSA_REGISTER_FLAGS_PRIVILEGED        0x0001
40 #define XTENSA_REGISTER_FLAGS_READABLE          0x0002
41 #define XTENSA_REGISTER_FLAGS_WRITABLE          0x0004
42 #define XTENSA_REGISTER_FLAGS_VOLATILE          0x0008
43 
44 void xtensa_count_regs(const XtensaConfig *config,
45                        unsigned *n_regs, unsigned *n_core_regs)
46 {
47     unsigned i;
48     bool count_core_regs = true;
49 
50     for (i = 0; config->gdb_regmap.reg[i].targno >= 0; ++i) {
51         if (config->gdb_regmap.reg[i].type != xtRegisterTypeTieState &&
52             config->gdb_regmap.reg[i].type != xtRegisterTypeMapped &&
53             config->gdb_regmap.reg[i].type != xtRegisterTypeUnmapped) {
54             ++*n_regs;
55             if (count_core_regs) {
56                 if ((config->gdb_regmap.reg[i].flags &
57                      XTENSA_REGISTER_FLAGS_PRIVILEGED) == 0) {
58                     ++*n_core_regs;
59                 } else {
60                     count_core_regs = false;
61                 }
62             }
63         }
64     }
65 }
66 
67 int xtensa_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
68 {
69     XtensaCPU *cpu = XTENSA_CPU(cs);
70     CPUXtensaState *env = &cpu->env;
71     const XtensaGdbReg *reg = env->config->gdb_regmap.reg + n;
72 #ifdef CONFIG_USER_ONLY
73     int num_regs = env->config->gdb_regmap.num_core_regs;
74 #else
75     int num_regs = env->config->gdb_regmap.num_regs;
76 #endif
77     unsigned i;
78 
79     if (n < 0 || n >= num_regs) {
80         return 0;
81     }
82 
83     switch (reg->type) {
84     case xtRegisterTypeVirtual: /*pc*/
85         return gdb_get_reg32(mem_buf, env->pc);
86 
87     case xtRegisterTypeArRegfile: /*ar*/
88         xtensa_sync_phys_from_window(env);
89         return gdb_get_reg32(mem_buf, env->phys_regs[(reg->targno & 0xff)
90                                                      % env->config->nareg]);
91 
92     case xtRegisterTypeSpecialReg: /*SR*/
93         return gdb_get_reg32(mem_buf, env->sregs[reg->targno & 0xff]);
94 
95     case xtRegisterTypeUserReg: /*UR*/
96         return gdb_get_reg32(mem_buf, env->uregs[reg->targno & 0xff]);
97 
98     case xtRegisterTypeTieRegfile: /*f*/
99         i = reg->targno & 0x0f;
100         switch (reg->size) {
101         case 4:
102             return gdb_get_reg32(mem_buf,
103                                  float32_val(env->fregs[i].f32[FP_F32_LOW]));
104         case 8:
105             return gdb_get_reg64(mem_buf, float64_val(env->fregs[i].f64));
106         default:
107             qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported size %d\n",
108                           __func__, n, reg->size);
109             memset(mem_buf, 0, reg->size);
110             return reg->size;
111         }
112 
113     case xtRegisterTypeWindow: /*a*/
114         return gdb_get_reg32(mem_buf, env->regs[reg->targno & 0x0f]);
115 
116     default:
117         qemu_log_mask(LOG_UNIMP, "%s from reg %d of unsupported type %d\n",
118                       __func__, n, reg->type);
119         memset(mem_buf, 0, reg->size);
120         return reg->size;
121     }
122 }
123 
124 int xtensa_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
125 {
126     XtensaCPU *cpu = XTENSA_CPU(cs);
127     CPUXtensaState *env = &cpu->env;
128     uint32_t tmp;
129     const XtensaGdbReg *reg = env->config->gdb_regmap.reg + n;
130 #ifdef CONFIG_USER_ONLY
131     int num_regs = env->config->gdb_regmap.num_core_regs;
132 #else
133     int num_regs = env->config->gdb_regmap.num_regs;
134 #endif
135 
136     if (n < 0 || n >= num_regs) {
137         return 0;
138     }
139 
140     tmp = ldl_p(mem_buf);
141 
142     switch (reg->type) {
143     case xtRegisterTypeVirtual: /*pc*/
144         env->pc = tmp;
145         break;
146 
147     case xtRegisterTypeArRegfile: /*ar*/
148         env->phys_regs[(reg->targno & 0xff) % env->config->nareg] = tmp;
149         xtensa_sync_window_from_phys(env);
150         break;
151 
152     case xtRegisterTypeSpecialReg: /*SR*/
153         env->sregs[reg->targno & 0xff] = tmp;
154         break;
155 
156     case xtRegisterTypeUserReg: /*UR*/
157         env->uregs[reg->targno & 0xff] = tmp;
158         break;
159 
160     case xtRegisterTypeTieRegfile: /*f*/
161         switch (reg->size) {
162         case 4:
163             env->fregs[reg->targno & 0x0f].f32[FP_F32_LOW] = make_float32(tmp);
164             return 4;
165         case 8:
166             env->fregs[reg->targno & 0x0f].f64 = make_float64(tmp);
167             return 8;
168         default:
169             qemu_log_mask(LOG_UNIMP, "%s to reg %d of unsupported size %d\n",
170                           __func__, n, reg->size);
171             return reg->size;
172         }
173 
174     case xtRegisterTypeWindow: /*a*/
175         env->regs[reg->targno & 0x0f] = tmp;
176         break;
177 
178     default:
179         qemu_log_mask(LOG_UNIMP, "%s to reg %d of unsupported type %d\n",
180                       __func__, n, reg->type);
181         return reg->size;
182     }
183 
184     return 4;
185 }
186